研究了QR码图像二值化技术,针对光照不均的QR图像提出了一种改进的基于背景灰度估计的校正算法.该算法首先根据原图像大小进行分块处理,在此基础上利用改进的灰度估计公式计算分块的灰度值,然后利用双线性内插法设置区块灰度值为估计值,最后用原图像减去估计背景图像得到校正图像,以此克服了光照不均对二值化阈值选取的影响.实验证明,该算法能够对灰度变换范围较大、光照不均的QR码图像进行有效的校正,得到良好的二值化图像.%This paper studies the binarization technique of QR code image and proposes an improved background gray-level based algorithm for uneven illumination QR code image. Firstly, it cuts the QR image as several blocks based on the size of original image, then evaluates the gray-value of each block and set block's gray-value with the bilinear interpolation method. Thirdly, it subtracts the estimated background image from original uneven illumination image get the corrected image, and with this method to eliminate the bad affection for binarization from nonuniform illumination.Experiments show that the algorithm can get a better QR binary image effectively for QR code image which has widespread gray-level and especially for uneven illuminated QR code image.
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